Retired Greens leader Bob Brown understood how to make a difference to the political agenda. Mr Brown’s political weapons of choice were peaceful protest and ­respectful debate.

For many years his commitment to protecting the environment for the benefit of future generations had a direct impact on public opinion and policy.

He was someone with whom you could disagree, as I often did, particularly on economic policy, while ­acknowledging he had a genuine commitment to ­environmental sustainability.

Contrast this approach to the latest ideological ratbaggery to come out of the NSW division of the Greens political party.

A newly formed Greens faction calling itself Left ­Renewal has pledged itself to destroy capitalism, which it says is based on “elitism, sexism, racism, homophobia, transphobia, religious sectarianism, and ableism”.

It also rejects the authority of the police because they “do not share an interest with the working class’’.

As bizarre as these positions are, I’m not surprised.

During this year’s election campaign, the NSW Greens selected as my opponent Jim Casey, who had previously openly advocated the return of an Abbott government.

“I would prefer to see Tony Abbott returned as prime minister with a labour movement that is growing, an anti-war movement that was disrupting things in the streets, with a strong and ­vibrant women’s movement, indigenous movement, and a climate change movement that was starting actually to disrupt the production of coal,” Mr Casey told a Greens strategy workshop in 2014.

“I’d prefer to see Abbott as the prime minister in that ­environment than Bill Shorten as prime minister without it.” Australians don’t want ­better demos. They want a better nation, one where opportunity is shared, where hard work brings fair rewards and people can access decent health and education services. The views of Left Renewal are at odds with participation in mainstream politics that sees parliament as the vehicle for change.

The Greens leader Richard di Natale has on ­occasions sought to distance himself from the hardliners in his party. He knows there is a chasm between the views of progressives who vote for the Greens, but who do not back the agenda of the Marxist revolutionary movements from which most of the Greens party Sydney leadership emerged.

However, Senator Di Natale has been more than happy to campaign with the hardliners in the NSW Greens, even as they sneer behind his back and deride him as “a tree Tory’’.

During last year’s election campaign, Senator Di Natale virtually set up camp in my electorate of Grayndler trying to elect Mr Casey, the so-called radical candidate who wanted Abbott to be prime minister.

Whatever Senator Di ­Natale says about his NSW colleagues, his actions speak to his preparedness to accept and even encourage views that are in conflict with the stated views of his party.

When Bob Brown called for a clean out of the NSW leadership, state Greens Party MP Mehreen Faruqi declared he had “broken her heart”.

Senator Di Natale seems content to continue to have his party in Australia’s biggest state dominated by people who rarely mention the environment and who have joined to advance agendas that are far removed from those they seek to represent.

Knowing they could not win support in mainstream politics, these hardliners have joined the Greens, hijacked its policy agenda and are now attempting to transform it into a ­vehicle for the agendas of their former revolutionary political parties.

The NSW division of the Greens and the members of Left ­Renewal are entitled to their opinions.

Those of us in mainstream politics who believe in progressive change through democratic processes are entitled to call them out for their views.

Bob Brown did that after the last election. It’s a pity Richard Di Natale does not have the authority to do the same.